At the present time rivet connections described above are the predominantly used splicing connections in aircraft construction.
In such conventional splicing connections an interlocking is achieved between the parts to be interconnected by a mechanical interlocking of geometric shapes to thereby provide an interlocking splice connection. In such connections it is necessary that the resistance of the inwardly facing walls of the rivet holes in the individual sheet metal portions and the shearing resistance of the rivets must be larger than the loads externally applied to the splice. Conventionally one or several rows of rivets are used in such splices of mutually overlapping sheet metal end portions, whereby full volume rivets, tight fit rivets, threaded rivets, or blind rivets are used. Typical examples for the connection of thin-walled structures are longitudinal and cross seams, as well as seams surrounding a repaired skin section. A multitude of rivet connections in an aircraft, particularly an aircraft body skin, is of basic importance for the flight characteristics of an aircraft. The rivets are individually dimensioned for the particular riveted splice taking into account the type of rivet, the size of the rivets, the spacing between the rivets and so forth, particularly paying attention to the local static and dynamic loads. In this connection it is an essential requirement that the splice has a high useful life and is substantially free of the need for inspections or requires only few inspections.
During the operation of an aircraft large areas or sections of the aircraft structure are subject to cyclical or dynamic tension loads. As a result, the components made of metallic materials are exposed to the potential danger of fatigue due to crack formations followed by crack progression or crack creeping. Individual cracks and particularly widespread fatigue damage caused by cracks can substantially reduce the strength characteristics of these metal components. These fatigue characteristics must be taken into account when inspection intervals are scheduled. In aircraft construction the thin-walled structures which have been optimized with regard to weight reduction are frequently subject to a high secondary bending load component, whereby a low crack resistance duration occurs which simultaneously requires a high inspection effort and expense. A secondary bending has been observed to occur when the load axis and the neutral phase are not identical in a structural component. For example, in the case of a splice interconnecting two overlapping sheet metal end portions the load axis and the neutral phase are staggered relative to each other.